Cylinder head



CYLINDER HEAD Filed Jan. 20, 1958 2 sheets-sheet 1 rf//l/ f ATTORNEYSJune 25, 1940. E. G. FAHLMAN 2,205,546

CYLINDER HEAD Filed Jan. 2o, 1938' 2 sheets-sheet 2 Z 5 0 n 6 l 6 Jlau 0a O 5l G ,./5 H(6 .m 6 755 3 h 2 Z 5 l a 0 5 6 El?, F 9 RJ ,.Md, R .d 45 .y/f/ .1 0G a .4 l l 5. T t 7 o o 1 6 x ,.7F ma mtl 7 4 ,l n a.. w45,V# .w 0 .1 L 3 0 y 5, EM xo o e O \0 5 :05 7% \5 6 ,6x 4 6 8 x 5 )L W.MW 5M, x4 x5 \N 1.. Z` Y #l 4 :Jn/v U3 4 o F 74 l L) .1 50. 8 6.9 Z F 25 5 118 w Jil 0 O l 5 a mi, E 04u 6 4. 1 4 04 l/um M f, ,1 5 4 AM .1 .w79 o 5 Z .L 6 1/ flo 44%5 v6 Z/v 5 9 4 M 3 G H 6 4 rll 5\ Af/JA a 7 2Jn4/ \\\/4 o1 6 Z 5 f/ 5 F 4 5 5 .L 0 54 v. G O 5 ./5 Z 6 6 0 Z o/O ./a 95 6 ATTORNEYS Patented `lune 25, 1940 PATENT OFFICE CYLINDER HEADEverett G. Fahlman, Lakewood, Cleveland, Ohio, assignor to The PermoldCompany, Cleveland, Ohio, a corporation of Ohio Application Januaryv 20,1938, Serial No. 185,881

. 1.0 Claims.

l This invention relates to liquid cooled cylinder heads for internalcombustion engines and has for its principal object the provision ofsuch a head of new and improved design and construction which willpermit a more desirable and eincient operation of an engine and issimple and inexpensive to manufacture.

Another object is to provide acylinder head having a compression walloverlying a combustion chamber and a cooling liquid chamber over n thecompression wall with means to reinforce the head against deflection,whereby the compression wall may be relatively thin.

Another object is to provide a means for reinforcing a cylinder headwhich does not objectionably interfere with the flow of cooling liquidthrough the cooling liquid chamber and which is adapted to variousdesigns of cylinder heads in order to furnish reinforcement at anyregion subject to strain.

Another object is to provide a cylinder head having a wall overlying acombustion chamber and an outer wall separated therefrom by a coolingliquid chamber with a reinforcing means associated with the vouter walland arranged to strengthen the wall voverlying the combustion chamber.

The usual method of attaching a cylinder head to the cylinder block ofan engine is by means of a plurality of cylinder head bolts whichv passthrough the cylinder head and are secured in the cylinder block. Theexplosion of a combustible mixture in the cylinder and combustionchamber of an internal combustion engine subjects the head thereof toconsiderable strain. One effect of an explosion in the combustionchamber is to cause the portion or portions of the cylinder head lyingbetween the bolts securing the head to the engine block to be deflected.

Such repeated deflection is very undesirable in those portions of thecylinder head which are disposed between adjacent cylinders becauseit islikely to result in blow-by or passage of gases from one cylinder toanother. Furthermore, the repeated deflections, particularly in` waterjacket. However, a gasket is usually insufficient to maintain thecombustion chamber in a sealed condition when deflection of the cylinderhead occurs under the high pressures of the explosion. Leakage of thecombustion gases 5 from the combustion chamberbetween the cylinder headand the top surface of, the engine block often occurs at pointsintermediate the hold-down bolts. This escape of gaseous products ofcombustion is commonly referred to as 1o blow-by, mentioned above. Sucha condition is undesirable, it interferes with the performance of anengine because of the loss of power involved and if continued for asufiicient period of time causes erosion or corrosion of the metal ofthe l5 cylinder head or engine block or both. Additionally, it mayresult in loss of liquid from the cooling system.

In order to minimize deflection of the lower or compression wall of acylinder head it is cus- 2'0 tomary to increase the thickness of suchwall. This practice, however, is objectionable because of the increasedweight of the cylinder head necessitated by the increased thickness ofthe cross-section and additional metal used to form 25 the head.

With an increase in the compression ratioy of an internal combustionengine the diiculties encountered as a result of deflection of the loweror compression wallrof the cylinder head, such 30" as blow-by andcracking thereof over the combustion chamber, are increased.Consequently, it is of paramount importance to perfect a cylinder headdesign which minimizes deflection of the lower or compression wall.Because of the 35 increased use in cylinder heads of metals ofrelatively high heat conductivity, such as aluminum and copper which arerelatively expensive, it is desirable that the strengthening of thelower wall of the cylinder head be accomplished 40 without resorting toexcessive increases inthe thickness thereof and the present inventionreshown in Fig. 1; 55,l

Fig. 4 is a sectional view taken on the line 4-4 of Fig. l;

Fig. 5 is a sectional View taken on the .line 5*-5 of Fig. 1;

Fig. 6 is a sectional view taken on the line G-G of Fig. l;

Fig. '7 is a sectional view taken on the line Z`-`f of Fig. 1;

Fig. 8 is a plan view of a cylinder head for six-cylinder engine blockconstructed in accordance with the present invention;

Fig. 9 is an elevational view partly in section on the line 9-9 of Fig.3;

Fig. l0 is a bottom View of the cylinder head shown in Fig. 8;

Fig. ll is a section on the line Iie-ii of Fig. 8;

Fig. 12 is a sectional view on the line |2|2 of Fig. 8; and

Fig. 13 is a sectional. View with parts broken away on the line |S|3 ofFig. 8.

Referring to Figs. l. through 7 by numerals of reference, which indicatelike parts throughout the several views, the cylinder head comprises atop wall indicated generally by the numeral I0 and a bottom wallindicated generally by the numeral 2E). The cylinder head is arrangedand intended to be applied to the engine block (not shown) of aninternal combustion engine so that each of the depressions orconcavities 2| formed in the lower wall of the cylinder head willoverlie a cylinder and inlet and exhaust valves to form a combustionchamber. Portions 22 of the bottom wall of the cylinder head whichsurround the concavities 2| lare formed to lie in close proximity to thetop surface of the engine block, so that by suitable means such as agasket (not shown) positioned between the portions 22 of the cylinderhead and the engine block each of the combustion chambers, including theconcavities 2|, are sealed from each of the other concavities andcombustion chambers, and from the atmosphere and the cooling liquidpassages.

Marginal stud bosses 3|, located at peripheral portions of the cylinderhead, and central stud bosses 32, are provided at suitably spacedintervals around and across the cylinder head. These stud bosses havecentral apertures 33 to receive suitable bolts or studs (not shown)which are secured in the engine block and fasten the cylinder head tothe engine block.

The top wall ID is spaced from the bottom or compression wall 20 andmarginal portions I I of the top wall are curved or otherwise formed tojoin with the bottom. wall 2U to provide an enclosed cooling liquidchamber I2. A number of liquid inlet openings 26 are formed in thebottom wall 2Q and arranged to communicate with suitable passages in thewater jacket of the cylinder block to provide a supply of cooling liquidto the cooling liquid chamber I2 of the cylinder head. All of the studbosses 3| and 32 extend entirely through the cylinder head and areclamped rigidly to the engine block by tightening of the cylinder headbolts. Those stud bosses positioned in intermediate portions of thecylinder head and extending through the cooling liquid chamber I2 arerelatively long and have intermediate portions 38 exposed to the coolingliquid. Some of the marginal stud bosses may be relatively short sincethe cooling liquid chamber I2 may not extend to all portions of thecylinder head. Portions of the top wall I D overlying the concavities 2|are formed to join with the bottom wall 20 to provide spark plug bossesI3 which are thus surrounded by the cooling liquid chamber.

As previously mentioned, the effect of the high pressures due toexplosions in the combustion chamber of the internal combustion engineis to cause a defiection of portions of the lower wall 2|). The amountof deflection of portions 23 which lie substantially close to studbosses is relatively small, whereas the portions of the bottom orcombustion Wall 20 which are relatively removed from the supportafforded by the stud bosses usually exhibit a greater deflection. Forexample, the portions 24 of the bottom wall 20 which form parts of theconcavities 2| are relatively far from the support of stud bosses and inthe absence of reinforcement would normally be subject to considerabledeiiection.

In the operation of an internal combustion engine where such deflectionis intermittent, there is a marked deleterious effect on the ma terialof the cylinder head which often results in its cracking, or otherfailure. If deflection occurs in the bottom wall 20 at the portions` 22which lie marginally of a concavity 2| then the gaseous products in thecombustion cham ber, which are under high pressure, are likely to escapetherefrom between the cylinder head and the cylinder blocknotwithstanding the gasket, since the latter is ineffective to seal thejoint between the engine block and the cylinder head when the bottomwall of the latter is excessively deiiected. This blow-by or escape ofthe gases from the combustion chamber causes a loss of power in theengine and erosion or corrosion of the metal thereof andis otherwiseobjectionable.

In accordance with the present invention, a post or pillar 40 is formedto extend between the bottom wall 2D and top wall ID through the coolingliquid chamber I2. In this manner the bottom wall 20 is reinforced orstrengthened by the top wall I0 so that in effect the resistance of thebottom Wall to deflection is substantially equivalent to that of thecombined strength of the bottom wall plus the top Wall. Preferably thepost or pillar 4D is positioned adjacent a portion 24 of the bottom wallso that it will reinforce that part most subject to excessivedeflection.

Reinforcing members or ribs 4| are formed in association with the topwall IU and materially increase its strength and resistance to bending.The stud bosses 3| and 32, being relatively rigidly secured to theengine block by the hold-down bolts, form convenient supports for theribs 4I.

Accordingly, it is desirable that the ribs extend between stud bossesand preferably are formed exteriorly of the top wall I0 as shown in Fig.6. Such a method of construction has a number of advantages. One suchadvantage is that the cooling liquid chamber is substantiallyunobstructed so that the reinforcing rib does not interfere with theiiow of the cooling liquid through the cooling chamber. Thus the topwall I0 can be constructed to lie in much closer proximity to the bottomwall 20 so as to provide a relatively thin cylinder head to obtain adesirable, efficient ow of the cooling liquid therethrough. In addition,a thin cylinder head may be constructed of substantially less amount ofmaterial than is used in a thick cylinder head, and, accordingly, ismore economical to manufacture.

It is desirable that the ends of the ribs 4| have an adequately strongconnection to the stud bosses. Consequently, in the event that the studbosses do not extend a sucient distance above the top vwall l of thecylinder head it is desirable that end portions 42 of the ribs be formedbelowv the top wall IIJ of the cylinder head in the cooling liquidchamber I2 and joined to the stud bosses. Thus, in effect, a strengthen-'ing member or rib is provided which extends across the top of thecylinder head with end portions extending below the top wall thereof andsecurely xed to the stud bosses and having a central portion positionedexteriorly of the of the rib 44 extending between the central stud boss34 and marginal stud boss 3E. Preferably the intersection 45 of the ribs43 and ill is arranged to lie directly over the pillar 40 extendingbetween the top walll and bottom wall 2G of f the cylinder head. In thismanner the compression wall of the combustion chamber of the engine isdirectly supported by the ribextending between stud bosses on the top ofthe cylinder head, and the strain due to explosions inA the combustionchamber are more effectively transmitted directly to the stud bosses andhold-down bolts.

In asimilar manner each ofthe posts or pillars 40 which is arranged tostrengthen a portion 24 of the bottom wall 2l] overlying a combustionchamber of the engine is positioned so as to underlie the intersectionof strengthening ribs 4I which extend across the top wall lll of thecylinder head between stud bosses. Accordf ingly, the compression wallof the cylinder head overlying each of the combustion chambers isstrengthened against objectionable deflection so that a more efficientand desirable operation of the engineresults and the cylinder head isless sub-ject to deterioration. In addition to the pillarsv 4D extendingtothe bottom `wall 20 of the cylinder head from the intersection 45 ofthe ribs 4l, auxiliary posts or pillars 4B are provided to reinforce themarginal portion 25 of the bottom wall 2B of the cylinder head which isadjacent the concavities 2| of the combustion chambers of the two middlecylinders. These auxiliary pillars 46 are' supported by two of thecentrally extending ribs 4l which are joined to a central stud boss.indicated by the numeral 49.

Thus the marginal portions 25 of they bottom wall of the cylinder headare reinforced against excessive deflection so that blow-by-between thecombustion chambers and water jacket is minimized. l

This strengthening of the cylinder head by means of ribs formedexteriorly of the top or outer wall of the cylinder head is of suchbeneflcial effect that the thickness of both the top wall Il) and bottomwall 20 may be materially lessened without objectionably affecting theefflciency of the cylinder head. Accordingly, an

appreciable economy may be realized in the manufacture of cylinder headsby employing the For example, the rib 43 Also, the bottom wall 20,strengthened by the pillars 40 and 46 from the ribs 4I, need not be asthick as would'be necessary in the absence of the ribs. Furthermore,this thinning or reduction of thickness `of the lower wall 20 enables amore efficient transfer of heat from the combustion chamber of theengine to the cooling liquid chamber I2 of the cylinder head.

Another feature of a cylinder head constructed in accordance with thepresent invention relates to the casting of such a cylinder head in achill or permanent mold or a sand mold having chills in associationtherewith. Because of the relatively thin cross-section of each of theribs 4I and because of their formation on the exterior of the cylinderhead, where substantially their entire surface can be arranged incontact with the metallic mold section of a permanent or semi-permanentmold or with a chill of a sand.

mold, such ribs may be quickly solidified in the casting operationstoproduce a desirable crystalline structure in the metal or alloy fromwhich the cylinder head is cast. Accordingly, the ribs 4l are ofincreased strength relative to the quantity' of metal used and thecylinder head is t'hus stronger and lighter than those constructedaccording to usual design.

As previously mentioned, the absence of strengthening ribs within thecooling liquid chamber I2 permitsthe use of a relatively thin headA inwhich the cooling liquid chamber is relatively shallow, so that no deeppools of cooling liquid form and a' proper flow of the cooling liquidmay be obtained and regulated as regards kvelocity and direction offlow. Thus the cooling liquid may sweep over the bottom wall 28 of thecylinder head from the liquid inlet passages 25 to the cooling liquidoutlet i4.

The strengthening ribs former in association with the top or` outer wallI!) of the cylinder head may be `arranged in various positions accordingto the requirements of any particular design. For example, the ribs maybe located 'as shown on the cylinder head illustrated in Figs.

8 through 13. This head is designed for application to an internalcombustion engine cylinder block having six cylinders and cylinder headparts previously described in connection with the cylinder headillustrated in Figs. 1 through 7 have been indicated by the samenumerals of reference. It is proposed that the thickness of the topiwall Hl of this cylinder head be constructed considerably thinner thanthat which ordinarily would be requiredl inthe absence of the use of thestrengthening ribs provided by the present invention. Accordingly, inorder to give sufcient strength to the cylinder head a plurality ofperipheral ribs 5!) arev provided. These ribs in effect provide asubstantially continuousrib extending about the peripheral portions ofthe cylinder head between the marginal stud bosses 3l. l l

In an internal combustion engine with which the cylinder headillustrated in 8 to I3 may be used the cylinders may be offsetsubstantially with respect to the spark plug bosses i3 so thatthefprojection ofthe cylinder walls would appear as the broken linecircles 27 on the bottom Wallv 20 of the cylinder head, (see Fig. l0).This offset of the valves and'spark plugs with respect to the" cylinder,which occurs in what is commonly referred to as anL-head engine,necessitates a` relatively elongated combustion chamber. The combustionchamber is formed by the recessedor concave portion 2l of the bottom ofthe cylinder head and the upper or compression end of the cylinder whichis overlaid by a portion of the bottom wall 2i) of the cylinder head.Because of the relatively large area of the bottom wall 2li of thiscylinder head exposed to the high pressiues of explosions in thecombustion chambers, auxiliary posts or pillars are formed between thetop wall i6 and bottom wall 2li through the cooling liquid chamber Thesepillars are supported by the auxiliary ribs which extend betweensuccessive stud substantially through the central portion of thecylinder head.

The pillars 40 which reinforce the compression walls of the cylinderhead are variously supported. In each case, however, these pillarsextend between the top wall ifi and bottom Wall EB through the coolingliquid chamber i2. The compression walls of the cylinder head whichoverlie the cylinders at each end of the cylinder head, have posts orpillars ill supported by'cross ribs 5i and E52, rib El extending from amarginal stud boss El? positioned in the corner of the cylinder head toa central stud boss 6i. lThe ribs 52 extend between marginal stud bosses62 positioned centrally in each end of the cylinder head and marginalstud bosses $3 which are positioned between the end cylinders and thenent adjacent cylinders. The pillars 46 extending between the top andbottom walls overlying the end combustion chambers preferably arepositioned beneath the intersection 53 of the crossribs 5i and 52.

The pillars fill, to strengthen the walls of the cylinder head overlyingthe combustion chambers ci the cylinders next adjacent the endcylinders, are supported by supplementary ribs 511 which are formedexteriorly of the outer or top wall lil of the cylinder head, and extendbetween a central portion of peripheral ribs 5B and auxiliary ribs lil'.Thus the rib design over each of the cylinders next adjacent the endcylinders is in the form of an H, the supplementary ribs 54 beingcarried by the peripheral and auxiliary ribs with which they intersectand indirectly carried by the stud bosses which carry the peripheralribs 5D and auxiliary ribs 41.

Each of the pillars lll which strengthen the combustion walls overlyingthe two central cylinders is supported by a tln'ee-membered rib. Onemember 55 extends longitudinally of the cylinder head and each endthereof is formed into two divergent ribs 56 and 5i which comprise theother two members of the three-membered ribs. Euch of the divergent ribmembers 51 is secured to a marginal stud boss and each rib member 56 issecured to a central stud boss Ed. The pillars itl which are reinforcedby the three-membered ribs are preferably arranged to underlie theintersection of the rib members 5G, and 5l'. Thus a double Y- shapedstrengthening reinforcement is provided for the pillars of the twocentral combustion faces of the bottom wall 2Q of the cylinder head.

Transverse ribs '58 and 59 are also provided in this design of thecylinder head. The transverse ribs 58 are positioned between centralstud bosses and marginal stud boss. These ribs materially increase therigidity and strength of the upper wall lil of the cylinder head and ifdesired may cooperate with supplementary posts or pillars 48 whichextend through the cooling liquid chamber l2 between the top wall Il)and bottom wall 2E! of the cylinder head and serve to prevent delectionof the narrow portions 28 of the bottom wall of the cylinder head whichextend between adjacent combustion chambers of the engine. Thisconstruction minimizes the likelihood of the narrow portions 28 of thebottom wall 20 becoming suliciently deflected or separated from the vtopof the engine block to permit blow-by to occur between adjacentcombustion chambers.

The 'transverse ribs 59 are arranged to strengthen and reinforce theportions of the cylinder head between adjacent cylinders, particularlythe narrow portions 29 of the bottom wall 2i) of the cylinder head.Supplementary pillars i9 extend between the top and bottom walls of thecylinder head over the portions 29 of the bottom wall so that the bottomWall may be reinforced by the transverse ribs 59 'to minimize blow-bybetween adjacent cylinders of the engine.

In a cylinder head such as that illustrated in Figs. 8 through 13 therewill be no objection to a slight obstruction of the flow of coolingliquid through the cooling liquid chamber l2, since in addition to themain cooling liquid outlet 5, auxiliary cooling liquid outlets I6, lland l are provided. Accordingly, many of the ribs may be formedpartially in the cooling liquid chamber as shown in Fig. 13. f madeaccording to this practice, an outer or exposed portion 'ID of the ribsmay be formed exteriorly of the top Wall I0 of the cylinder head and theinternal portion 'H may underlie the exposed portion 'I0 and bepositioned wholly within the cooling liquid chamber l2. In such aconstruction, of course, the top wall it? of the cylinder head maybe'formed integrally with and joined directly into the sides of theribs, and the pillar or post 40 may similarly be formed into theinternal portion 'H of the rib. Even with the use of such a rib, aportion of which is positioned within the cooling liquid chamber, it isto be noted that there is no obstruction to the now of cooling liquidover the bottom wall or compression wall of the cylinder head.Consequently, there is no substantial impairment of the cooling actionover the portions of the bottom wall which are in contact with the hotgases inthe combustion chamber.

Cylinder heads constructed in accordance with the present inventionexhibit an additional feature which renders their cooling action moreefiicient and desirable for use with internal combustion engines. Thisfeature relates to the heat radiating eiect of the ribsl themselveswhich is particularly noticeable in such cylinder heads constructedormetals having the property of rapid heat conduction such as copper andaluminum and their alloys. area exposed to the rapidly moving air blownover the exterior surface of the cylinder head by the fan of the coolingsystem of the engine has an appreciably increased heat dissipatingproperty which tends to improve the operation of the engine and reducethe load on the liquid cooling system.

The lpresent invention thus provides an improved and novel method forstrengthening and reinforcing both the upper and lower walls of thecylinder head for an internal combustion engine. This reinforcementinvolves only a minimum interference with the flow of cooling liquidthrough the cylinder head and enables the cylinder head to beconstructed of an appreciably less amount of material so thatsubstantial economies may be realized in its manufacture and which alsoincreases its efficiency of performance.

The additional surface f:

t is to be understood, however, that the cylinder head designsillustrated in the drawings and described above are given for purposesof explanation only and it is contemplated that numerousmodifications-thereof with alterations in the shape and position ofthe'ribs and pillars are contemplated and intended to be included withinthe scope of the appended claims.

What I claim is:

1. An internal combustion engine cylinder head having a compression wallto overlie an 'engine combustion chamber', an outer wall spaced from thecompression wall to provide a cooling liquid chamber between the walls,a pluralityv of stud bosses for receiving hold-down bolts to secure thehead to an engine-block, and reinforcing ribs extending between` thebosses to strengthen the head, said ribs connected to the studbosseswithin the cooling liquid chamber and having a central portionformed on the exterior` of the outer wall whereby the rib presents aminimum resistance to the iiow of cooling liquid.

2. A cylinder head for an internal combustion engine comprising acompression Wall to overlie a combustion chamber of an engine, an outerwall spaced from the compression wall to provide a cooling liquidchamber between the walls, a plurality of stud bosses connected to bothwalls and having apertures extending therethrough for receivinghold-down bolts to secure the head to an engine block, at least one ofsaid stud bosses extending through the cooling liquid chamber betweenthe walls and having a central part substantially completely surroundedby the cooling liquid chamber, a projecting rib integrally formed on theouter wall to reinforce the latter, the major part of said rib beingdisposed outside of the cooling liquid chamber and one end of said ribextending into the cooling liquid chamber in the region of said lastmentioned stud boss and secured to the central part of said stud boss. v

3. A cylinder head for an internal combustion engine comprising acompression wall to overlie a combustion chamber of an engine, an outerwall spaced from the compression wall to provide av cooling liquidchamber between the walls,

a projecting rib integrally formed on the outer wall to reinforce thesame, the major part of said rib being disposed outside of the coolingliquid chamber, and a post extending through the cooling liquid chamberbetween said walls, said post having one end secured to the compressionwall at a portion of the latter which normally overlies a combustionchamber of an engine, and the other end of said post secured to theouter wall at a region of the latter adjacent a central portion of saidrib.

4. A cylinder head for an internal combustion engine comprising acompression wall to be secured to the block of an internal combustionengine and having portions for overlying the combustion chambers of anengine, an outer wall spaced from the compressionwall to provide acooling liquid chamber between the walls, a plurality of inlet openingsformed in the compression wall to admit cooling liquid to the chamber,an outlet through which cooling liquid is withdrawn from thev chamber,said outletbeing remote from the inlets to provide a flow of coolingliquid through the chamber in directions substantially paralleling thewalls thereof, and integral ribs` formed on the outer wall andprojecting therefrom to reinforce the same, the major part of each ofsaid ribs being disposed wholly outsideV of the cooling liquidchamber toavoid obstructing the flow through the chamber, said inlets and outletbeing disposed so that the ow of cooling liquid through the chamber islargely transverse to the length of the ribs.

5. A cylinder head for an internal combustion engine comprising anintegral casting having a compression wall to be disposedagainst a blockof an engine with portions thereof overlying coml bustion chambers ofthe engine, an outer wall spaced from the compression wall to yprovide acooling liquid chamber between the walls, a plurality of 'stud bosseshaving apertures therethrough for receiving hold-down bolts to securethe head to an engine block, a plurality of integral ribs formed on theouter wall, said ribs having their ends secured to some of said studbosses, and integral posts extending between the outer wall andcompression wall, one end of each of said posts being formedj into oneof the compression wall portions which 'overlies avcombustion chamber,and the opposite end of each of said posts being formed into the outerwall adjacent a central part of one of said ribs, whereby deflection ofthe compression wall both toward and away from the outer wall isresisted by the posts and ribs.

6. An engine cylinder head construction comprising a compression wall tooverlie an engine combustion chamber, an outer wall spaced from thecompression wall to provide a cooling liquid chamber between the'walls,a pair of ribs integrally formed on the outer wall and projectingoutwardly therefrom, said ribs being crossed and the major portions ofthe ribs being disposed outside of the cooling liquid chamber, and apost extending through said chamber between said walls, said post havingone end secured to the compression wall at a portion of the latter whichnormally overlies an engine combustion chamber, and the other end ofsaid post secured to the outer wall at a region of the latter adjacentthe crossing of the ribs.

7. An engine cylinder head construction comprising a compression wall tooverlie an engine combustion chamber, an outer wall spaced from thecompression wall to provide a cooling liquid chamber between the walls,spaced bosses integral with the outer wall for supporting the same andsecuring the head to an engine block, a rib integrally formed on theouter wall and projecting outwardly therefrom, said rib extendingbetween spaced bosses and having each of its ends connected to a bossover a distancegreater than the thickness of the outer wall, and a postextending through the cooling liquid chamber between said walls, saidpost having one end secured to the compression wall and the other endsecured to the outer wall at a region of the latter adjacent a centralportion of said rib.

8. An engine cylinder head construction comprising a compression wall tooverlie an engine combustion chamber, an outer wall spaced from thecompression wall to provide a cooling liquid chamber between the walls,an attaching boss integral with the outer wall for supporting the sameand securing the head to an engine block, a rib integrally formed on theouter wall and projecting outwardly therefrom sufliciently so that themajor part thereof is disposed outside of the cooling liquid chamber,said rib extending laterally from said boss and having one end connectedtothe boss over a distance greater than the thickness of the outer wall,and a post extending through the cooling liquid chamber between saidwalls, said post having one end secured to the compression wall and theother end secured to the outer wall at a region of the latter adjacentsaid rib whereby the rib and post cooperatively resist deflection of thecompression wall and transmit to the boss forces applied to thecompression wall by the burning of fuel in the combustion chamber of theengine.

9. An engine cylinder head construction comprising a compression wall tooverlie an engine combustion chamber, an outer wall centrally spacedfrom the compression wall and marginal- 1y connected thereto to providea cooling liquid chamber between the walls, spaced bosses integral withthe outer wall for supporting the same and securing the head to anengine block, and a rib integrally formed on the outside of the centralpart of the outer wall and projecting outwardly therefrom so that themajor portion of the rib is disposed wholly outside of the coolingliquid chamber and is exposed to the atmosphere, said rib extendingbetween a pair of said spaced bosses and having each of its endsconnected to a boss over a distance greater than the thickness of theouter wall.

10. An engine cylinder head construction comprising a compression Wallto overlie an engine combustion chamber, an outer wall centrally spacedfrom the compression wall and marginal- 1y connected thereto to providea cooling liquid chamber between the walls, spaced bosses integral withthe outer wall for supporting the same and securing the head to anengine block, and a pair of ribs integrally formed on the outside of thecentral part of the outer wall and projecting outwardly therefrom sothat the major portion of each rib is disposed wholly outside of thecool- Y ing liquid chamber and is exposed to the atmosphere, said ribsbeing crossed and each extending between a pair of said spaced bosses,each end of the crossed ribs being connected to a boss over a distancegreater than the thickness of the outer Wall.

EVERE'IT G. FAHLMAN.

